Once again, an extreme retreat of Alaskas summer sea ice has led large numbers of Pacific walruses to haul out on land instead of resting on offshore ice. This is a spectacle that has become all too common in six of the last eight years, a result of climate warming. Summer sea ice is retreating far north of the shallow continental shelf waters of the Chukchi Sea in U.S. and Russian waters, a condition that did not occur a decade ago. To keep up with their normal resting periods between feeding bouts to the seafloor, walruses have simply hauled out onto shore. Hauling out refers to the behavior of temporarily leaving the water for sites on land or ice. The USGS is tracking walruses with satellite radio-tags to better understand how sea-ice retreat is affecting these large pinnipeds. The population-level effects of these behavioral hauling-out changes are not yet understood; however, USGS and other researchers do know that while onshore, young walruses are susceptible to mortality from trampling. Also, hauling out on shore and using nearshore feeding areas may be energetically less profitable than their preferred behavior of using the ice as a platform on which to rest while remaining near rich feeding grounds. https://youtube/watch?v=rH77gte9lVI Check full story here: on.doi.gov/ZsrMcP
Posted on: Wed, 01 Oct 2014 21:02:03 +0000
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